Diaphragm



H. 'JOYCE DIAPHRAGM May 6, 1924. 1,492,989

Filed Dec. 13. 1922 Patented May 6, 1924.

UNITED STATES PATENT OFFICE.

HERBERT JOYCE, F WASSAIC, NEW YORK, ASSIGNOR OF ONE-HALF T0 FREDERICK G.

ASHLEY, OF BROOKLYN, NEW YORK.

DIAPHRAGH.

Application led December 13, 1922. Serial Io. 608,586.

To all whom it may concern:

VBe it known that I, HERBERT J oxen, a subject of the King of Great Britain, and a resident of Wassaic, Dutchess County, State of New York, have invented certain new and useful Improvements in Diaphragme, of which the following is a specification.

This invention relates to diaphragms for be reproducing sound and is herein illustratedy as applied to the sound box of a well known form of phonograph, adapted to reproduce what are known as hill and dale records. According to the present invention, a suitable diaphragm base is coated with wax prefer-` ably out to the very edge of the mounting of the diaphragm, so that there is a continuous coating of wax over the entire area of the diaphragm which is exposed tothe air. The diaphragm base upon which the coating is applied is preferably a rigid, resilient sheet,-

an ordinary mica diaphragm forms an excellent base for the purpose. In the form herein illustrated the wax is applied only to one side of the mica, the side remote from the tone-arm or horn. It is found advanta us to apply two layers of wax; one fairly rd layer, such as parain wax of one of the higher melting points, and above that to apply a second wax coating of a softer wax lo such as beeswax. Coatings of various thicknesses have been found useful and the most satisfactory coating has been found to be one in which the two'la ers are each slightly less than 116 of an inc thick. Other feau tures and advantages will hereinafter ap- In the accompanying drawin Fig. 1 is a rear view of a sound. box s owing the coating of the diaphragm.

4o Fig. 2 is a sectional side view showinglthe rigid resilient base and the two layers o wax superposed thereon.

A nuca sheet 1 forming a well known kind of diaphragm is held by a screw 2 to the long arm 3, pivoted at 4, of the needle lever which carries on its other arm 5 a needle 6. The mica sheet 1 is held between two rubber gaskets 7 and 8 in any usual or desired manner, the gaskets support' the 5o dia hragm on the opposite sides and ing hel against it by the usual body 9 and its turned over edge 10 which forms a supporting frame. The screw 2 is centrally located in thediaphragm opposite the opening 11,

to 124 melting point which leads tothe tone-arm (not shown). According to the resent invention the mica or other sheet 1 1s lcoated with a layer of paran wax 12, preferabl `by melting 122 i paraihn wax and ourlng a. suitable quantity while very liquid upon the horizontal cold sheet 1, which may at room tem rature. Preferably the coatlng thus app ied is somewhat less than 11g of an inch thick. When this coating is thoroughly cold a similar coating 13 of beeswax is made upon the outside of the paraiin Wax 12 by pouring upon it melted beeswax hot enough to flow freely so as to make a layer of the same thickness, but not hot enough to melt away the underlying layer of paraflin wax. When the coatings are cold the diaphragm is ready for use. If the coatings extend entirely up to the metal edge l or margin' 10 of the diaphra mounting and appear to adhere to the e, it will be found that sound is reproduced practically free from the scratching, which is ordinarily heard from sound records. The improvementvin the reproduction is particularly notioeable in the clearer reproduction of the hi h notes.

aving thus described way of example, what I claim and desire to secure by Letters Patent is:

1. An acoustic diaphragm havin asso ciated therewith layers of wax of dlierent degrees of hardness.

2. An acoustic diaphragm havin associated therewith layers of wax ofl 'dlferent degrees of hardness, the wax of one layer being of lower melting point than the wax of the other of said la ers.

3. .An acoustic iaphra having associated therewith a layer o wax upon which is superimposed a softer .layer of wax.

4. An acoustic diaphragm having associated therewith a layer of wax upon which is .superim osed a layer of wax the melting ptnt of w 'ch is less than of the wax of the I mentioned layer. s l 5. An acoustic diaphragm having a layer of parailin wax, and a layer of beeswax asso ciated therewith.

A6. `.An acoustic diaphragm having associated therewith a layer of paraffin wax upon which is superimposed a layer of beeswax.

7. The combination with a frame of an Aacoustic instrument, of a diaphragm having my invention, by

attached to one side thereof a coating of wax, said wax being attached to said frame adjacent the periphery of said diaphragm. 8. The combination with a frame of an a acoustic instrument, of a diaphragm having associated therewith layers of wax attached to said frame adjacent the periphery of said diaphragm 9. The combination with a' diaphragm Lacasse support, of an acoustic diaphragm supporb. 10

ed by said support and having associated therewith a layer of paran' wax and a iayer of beeswax, said layers of wax being adhesively attached to said support adjacent the periphery of said diaphragm.

ln testimony whereof, I have aixed my signature to this specification.

HERBERT JOYCE. 

